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Modern Ontario ADU exterior with charcoal cladding and warm cedar accents
ADU types

Five ways to add a second home, designed for Ontario.

Every lot is different. Compare the five suite types we take on, with realistic Ontario cost, rent, timeline and value-add estimates for each.

Bright finished basement suite with modern kitchen and large egress windows
Basement suite

Basement Suite

A basement suite turns under-used lower-level square footage into a legal, self-contained rental or family unit. It's the fastest and most budget-friendly path to income because the structure and footprint already exist. The work centres on egress windows, ceiling height, fire separation, a separate entrance and a compliant kitchen and bath. Done well, a basement suite feels bright and intentional, not like an afterthought.

Typical cost
$60K–$120K
Rent potential
$1,400–$2,400/mo
Timeline
8–14 wks
Value-add
+$120K–220K

Best fit

  • Homeowners wanting the lowest-cost entry to ADU income
  • Properties with adequate ceiling height and a viable separate entrance
  • Owners comfortable with a smaller, efficient layout

Pros

  • Lowest typical cost of any ADU
  • Quickest timeline to occupancy
  • No loss of yard or parking
  • Uses existing structure and services

Trade-offs

  • Constrained by existing ceiling height
  • Egress and light require careful design
  • Smaller footprint than detached suites

Zoning & build considerations

  • Requires a code-compliant second egress and minimum ceiling height under the Ontario Building Code
  • Fire separation between units is mandatory
  • A separate, accessible entrance is typically required
  • Most municipalities register basement suites as a second unit under Bill 23
Request pricing for a basement suite
Modern attached suite addition blending with an existing brick home
Attached suite

Attached Suite

An attached suite is an addition that extends your home to create a connected but independent dwelling. It suits families who want proximity: a teen suite, an in-law wing, or a rental that shares a wall but not a front door. Because it's purpose-built, layouts are generous and finishes are seamless with the main house. It preserves more yard than a detached suite while offering more space than a basement.

Typical cost
$80K–$180K
Rent potential
$1,800–$3,200/mo
Timeline
12–20 wks
Value-add
+$150K–280K

Best fit

  • Multigenerational families wanting connection with independence
  • Lots with side or rear room to extend the home
  • Owners prioritising space and finish over lowest cost

Pros

  • Purpose-built, generous layouts
  • Blends architecturally with the main home
  • Preserves most of the backyard
  • Strong family and rental flexibility

Trade-offs

  • Higher cost than a basement conversion
  • Reduces some side or rear yard
  • May trigger setback and lot-coverage review

Zoning & build considerations

  • Subject to setback, height and lot-coverage limits in your zoning bylaw
  • May require a building permit and, occasionally, a minor variance
  • Servicing may be shared with or separated from the main home
  • Counts toward the unit limit permitted on your lot under Bill 23
Request pricing for a attached suite
Above-garage suite exterior with dormer windows glowing warm at dusk
Above-garage suite

Above-Garage Suite

An above-garage suite places a private dwelling over a new or existing garage, keeping vehicle storage below while building up rather than out. It works beautifully for a home office, a rental, or an independent space for family, with its own stair and entrance for genuine privacy.

Typical cost
$100K–$200K
Rent potential
$1,700–$3,000/mo
Timeline
14–22 wks
Value-add
+$160K–300K

Best fit

  • Owners with a suitable existing or planned garage
  • Lots where building up preserves yard space
  • Those wanting a clearly separate, private entrance

Pros

  • Efficient vertical use of the footprint
  • Keeps garage / parking below
  • Genuine privacy with a separate stair
  • Distinctive, characterful exterior

Trade-offs

  • Existing garage may need structural upgrades
  • Stair access reduces accessibility
  • Servicing the upper level adds cost

Zoning & build considerations

  • Height and storey limits in the zoning bylaw apply
  • Existing garage foundations and framing may require engineering review
  • A code-compliant stair and egress are required
  • Treated as a detached or accessory ADU depending on configuration
Request pricing for a above-garage suite
Single-story modern garden suite in a backyard at golden hour
Garden suite

Garden Suite

A garden suite is a detached, self-contained home in your backyard. It delivers the strongest blend of privacy, income and design freedom, with no shared walls and a true sense of a separate residence. Ontario municipalities increasingly support garden suites as gentle density, and many offer pre-approved plans or streamlined approvals. It suits owners who want maximum design freedom and long-term value.

Typical cost
$150K–$400K+
Rent potential
$2,200–$3,800/mo
Timeline
20–32 wks
Value-add
+$200K–400K

Best fit

  • Owners with a generous backyard and rear access for construction
  • Those wanting maximum privacy and design freedom
  • Homeowners seeking strong income and value uplift

Pros

  • Fully detached, no shared walls
  • Strong rental income and value uplift
  • Design freedom on layout and finish
  • Supported by many Ontario municipalities

Trade-offs

  • Higher cost and longer timeline
  • Reduces backyard space
  • Servicing trenching to the main line adds cost

Zoning & build considerations

  • Subject to maximum size, height, setback and lot-coverage rules
  • Conservation authority approval may be required near floodplains or ravines
  • Servicing (water, sanitary, hydro) is run from the main home or street
  • Toronto and others offer pre-approved garden suite plans to speed approvals
Request pricing for a garden suite
Two-story Toronto laneway suite with brick and dark cladding facing a laneway
Laneway suite

Laneway Suite

A laneway suite is a detached home facing a public rear laneway: the premium urban ADU, common in Toronto and emerging in other cities. It often rises to two storeys, making efficient use of tight urban lots and commanding strong rents in central neighbourhoods. Approvals are more involved, but the result is a striking, independent residence with its own laneway address and entrance.

Typical cost
$200K–$450K+
Rent potential
$2,400–$4,200/mo
Timeline
22–34 wks
Value-add
+$220K–450K

Best fit

  • Urban lots with frontage on a maintained public laneway
  • Owners in high-rent central neighbourhoods
  • Those wanting a premium, architecturally ambitious build

Pros

  • Two storeys possible, strong floor area
  • Commands premium urban rents
  • Distinct laneway address and entrance
  • High value uplift in central locations

Trade-offs

  • Highest typical cost
  • Most involved approval process
  • Requires qualifying public laneway access

Zoning & build considerations

  • Requires frontage on a qualifying public laneway with access for emergency services
  • Toronto and Ottawa publish specific laneway / coach-house requirements
  • Angular planes, height and separation distances are closely reviewed
  • Toronto offers pre-approved and certified laneway plans
Request pricing for a laneway suite
Build methods

Custom, prefab, or modular.

Custom-built

Fully bespoke design and on-site construction tailored to your lot, taste and budget. The most design freedom and the right call for distinctive sites.

Prefab panelised

Wall and roof panels are fabricated off-site for speed and precision, then assembled on your property, shortening the weather-exposed build window.

Modular

Volumetric modules built in a controlled factory and craned into place. Fast and consistent where site access and crane logistics allow.


Not sure which suite fits your lot?

Start with a free feasibility-first consultation, or run the numbers yourself.

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